This invention relates to an apparatus for positioning a part of a vehicle body secured to a mount in an automobile assembly line.
An automobile assembly line usually includes plural mounts adapted to hold bodies and the bodies are progressively transferred to a particular assembly station by a transfer device. Also disposed in the assembly station is an apparatus for positioning a part of the body. The part is accurately positioned by the positioning apparatus and attached to the body on the mount by welding robots located at the assembly station along the line, thereby joining the part and the body into a completed body.
Referring to FIG. 2, there is illustrated a prior art positioning apparatus used in placing a rear panel for a particular automobile model at a predetermined attachment position relative to a body held by a mount. The positioning apparatus designated at 1 includes a platform 2 rotatably supported by a pivot 3 and having part locators 2a, 2b for holding a part in the form of a rear panel W in a predetermined attitude. A body 4 is set at a predetermined position on positioning posts 5 of the mount. The part W is placed on and held by the locators 2a, 2b of the platform 2 in a horizontal rest position such that the part W may take a predetermined attitude. The platform 2 having the part W held thereon is then rotated an angle of 90 about the pivot 3 in the direction of arrow A whereupon the part W is moved in place to the rear of the body 4, that is, the part W is placed at a predetermined position with respect to the body 4. A stationary stopper 6 serves to restrict the rotation of the platform 2 at the position of 90.degree. and to hold the rotated platform 2 in vertical orientation.
FIG. 3 shows another prior art positioning apparatus which can accommodate bodies of plural automobile models having different body lengths. The positioning apparatus disignated at 11 includes a frame 12, a slide base 13 mounted on the frame for back and forth sliding motion, and platform 15 supported for rotation on the slide base 13 by a pivot 14. A body 16 on a mount (not shown) is set at a predetermined position. A rear panel part W is placed on and held by part locators 15a, 15b of the platform 15 in a horizontal rest position such that the part W is in a predetermined attitude. The platform 15 having the part W held thereon is then rotated an angle of 90.degree. about the pivot 14 whereupon the part W is placed at a pedetermined position behind the body 16. To accommodate bodies 16a and 16b having different lengths, the slide base 13 is slidingly moved forward (to the left as viewed in FIG. 3). The positions at which the slide base 13 comes to stop upon forward movement are determined by stopper 17 for the body 16a and 18 for the body 16b secured to the frame 12 respectively.
In the positioning apparatus 1 and 11 illustrated in FIGS. 2 and 3, the part locators 2a, 2b and 15a, 15b for holding the part W in the predetermined attitude are fixed to the platforms 2 and 15.
Generally, in a body assembly line with plural automobile models, each mount for mounting a part has a set of switchable locators for locating the part W in the predetermined attitude. These locators are switched in accordance with the body lengths. In such a case, the locators on the mount may desirably be replaced by another set of particular locators corresponding to the length of a particular body in process. FIG. 4 illustrates a further positioning apparatus 21 which is provided with a platform and two locator supports 23 and 24 projected from a platform 22 so as to accommodate bodies of two automobile models having different body lengths and figures. A rotating block 25 having locator 25a and 25b of different lengths and figures is pivotably connected to one locator support 23, and another rotating block 26 having locator 26a and 26b of different lengths and figures is pivotably connected to the other locator support 24. To locate a part W, the locator 25b and 26b are selected. To hold another part (not shown), the rotating block 25 and 26 are turned to index the other locator 25a and 26a.
A further example of prior art positioning apparatus is illustrated in FIG. 5. The positioning apparatus designated at 31 can accommodate bodies of four automobile models having different body lengths and figures. The apparatus includes a platform 32 having two locator supports 33 and 34 projecting therefrom. A rotating block 35 having four radially extending locators 35a, 35b, 35c and 35d of different lengths and figures spaced 90.degree. apart is pivotably connected to one locator support 33, and another rotating block 36 having four radially extending engaging arms 36a, 36b, 36c and 36d of different lengths and figures spaced 90.degree. apart is pivotably connected to the other holder support 34. A first set of locators 35a, 36a is used to hold and position a first part W. For bodies of the other models, the rotating block 35 and 36 are rotated to index any desired set of locators 35b and 36b, 35c and 36c, or 35d and 36d to hold and position a particular part corresponding to the selected body.
The prior art positioning apparatus 1 illustrated in FIG. 2 suffers from the disadvantage that it can deal with only those models having the same body length in the assembly line because the position of the pivot 3 is fixed. Since the locators are fixedly secured to the platform, the entire platform must be replaced to start the production of a new model in the line, requiring a longer time for a larger number of modifications along the line.
The prior art positioning apparatus 11 illustrated in FIG. 3 suffers from the disadvantage that the position of stops 17 and 18 are determined for particular models, modification required to match with a new model of a different body length takes a longer time at more locations along the line.
The prior art positioning apparatus 21 or 31 illustrated in FIG. 4 or 5 can readily meet two or four models by changing locators, but fails to deal with a more variety of models. When the vehicle model is changed, the necessary modification of the positioning apparatus takes a great amount of time and labor and adds to the overall number of modifications.
Japanese Patent Application Kokai No. 60-252078 discloses an apparatus for carrying and positioning window glass. The apparatus includes a conveyor for conveying a body resting thereon, a running rail supported by a parallel rail above the body and adapted to travel along the parallel rail, a carriage adapted to travel along the conveyor, a suction unit for removably holding a piece of window glass, and a press unit for press fitting the window glass. In the window glass mounting step of the production line, this apparatus helps a worker to mount window glass to the body in that it automates those operations which can be performed without man labor and enables one worker to conduct the window glass mounting operation which otherwise needs two workers. With an angle adjustable press unit, the apparatus can readily accommodate a change of model. In the window glass carrying and positioning apparatus, however, the range which can be accommodated by adjusting the angle of the press unit is limited because the window glass held by the suction unit is carried and positioned. It is thus very difficult to apply this positioning apparatus to a body assembly installation.